New, cleaner package repository structure.

Package repositories now look like this:

    top-level-dir/
        repo.yaml
        packages/
            libelf/
                package.py
            mpich/
                package.py
            ...

This leaves room at the top level for additional metadata, source,
per-repo configs, indexes, etc., and it makes it easy to see that
something is a spack repo (just look for repo.yaml and packages).

var/spack/repos/builtin/packages/scalasca/package.py

@@ -0,0 +1,65 @@
+# FIXME: Add copyright
+
+from spack import *
+
+class Scalasca(Package):
+    """Scalasca is a software tool that supports the performance optimization
+       of parallel programs by measuring and analyzing their runtime behavior. 
+       The analysis identifies potential performance bottlenecks - in 
+       particular those concerning communication and synchronization - and 
+       offers guidance in exploring their causes."""
+
+    # FIXME: add a proper url for your package's homepage here.
+    homepage = "http://www.scalasca.org"
+    url      = "http://apps.fz-juelich.de/scalasca/releases/scalasca/2.1/dist/scalasca-2.1.tar.gz"
+
+    version('2.1', 'bab9c2b021e51e2ba187feec442b96e6', 
+            url = 'http://apps.fz-juelich.de/scalasca/releases/scalasca/2.1/dist/scalasca-2.1.tar.gz' )
+
+    depends_on("mpi")
+    depends_on("otf2@1.4")
+    depends_on("cube@4.2.3")
+
+    backend_user_provided = """\
+CC=cc
+CXX=c++
+F77=f77
+FC=f90
+CFLAGS=-fPIC
+CXXFLAGS=-fPIC
+"""
+    frontend_user_provided = """\
+CC_FOR_BUILD=cc
+CXX_FOR_BUILD=c++
+F77_FOR_BUILD=f70
+FC_FOR_BUILD=f90
+CFLAGS_FOR_BUILD=-fPIC
+CXXFLAGS_FOR_BUILD=-fPIC
+"""
+    mpi_user_provided = """\
+MPICC=mpicc
+MPICXX=mpicxx
+MPIF77=mpif77
+MPIFC=mpif90
+MPI_CFLAGS=-fPIC
+MPI_CXXFLAGS=-fPIC
+"""
+
+    def install(self, spec, prefix):
+        configure_args = ["--prefix=%s" % prefix,
+                          "--with-custom-compilers", 
+                          "--with-otf2=%s" % spec['otf2'].prefix.bin,
+                          "--with-cube=%s" % spec['cube'].prefix.bin,
+                          "--enable-shared"]
+
+        configure(*configure_args)
+
+        make()
+        make("install")
+
+        # FIXME: Modify the configure line to suit your build system here.
+        configure("--prefix=%s" % prefix)
+
+        # FIXME: Add logic to build and install here
+        make()
+        make("install")